1. Field of the Invention
The present invention relates, in general, to step stools which can be stacked one upon the other, and specifically to step stools having multi-purpose uses.
2. Description of the Prior Art
A number of known prior art devices are available which can be stacked, and also can be used for supporting scaffolding and the like, and/or use for other multi-purpose uses. However, known prior art type devices are rather complicated, fairly expensive and/or do not provide for the great number of work supporting and holding uses of the present invention.
Some prior art devices which may be pertinent to this invention are as follows:
E. J. Knipper U.S. Pat. No. 2,592,912--4/15/52 PA0 B. Parr U.S. Pat. No. 3,862,671--1/28/75 PA0 W. T. Ulerich U.S. Pat. No. 3,907,068--9/23/75 PA0 D. C. Steinbrecher U.S. Pat. No. 3,984,144--10/5/76 PA0 C. E. Morley U.S. Pat. No. D. 138,620--8/29/44 PA0 R. L. Culligan U.S. Pat. No. D. 242,423--11/23/76 PA0 J. M. Macho, et al. U.S. Pat. No. D. 265,026--6/22/82
None of these prior art devices offers the new and unique advantages of the present invention.
For example, the patent to Knipper, U.S. Pat. No. 2,592,912, discloses a combination foot stool, ladder, seat and storage chest. While this device does provide a number of multi-purpose uses, it is not designed to support low or medium height scaffolding, nor is it adapted for use in holding material to be worked upon in a secure and positive manner.
The patent to Parr, U.S. Pat. No. 3,862,671, shows a multiple step structure having a plurality of holes therein for making the device lightweight. However, these holes are not arranged for holding or securely retaining pipe or lumber type material for work thereupon. Such work holding and supporting features of the present invention are very important.
The patent to Ulerich, U.S. Pat. No. 3,907,068, shows a ladder block having a plurality of steps at different heights which can be used as a step ladder for reaching different heights depending on the size of the person using same. A pair of such blocks also can be used to support low or medium height scaffolding, i.e., boards therebetween for permitting a user thereof to work at different heights.
The patent to Steinbrecher, U.S. Pat. No. 3,984,144, shows a stepped desk cabinet for use by women and children. A horizontal flat desk top and a horizontal seat located therebelow and to the side thereof are supported by two step sides. A removable panel as a continuation of the seat serves as the top of the storage cabinet mounted by the removable panel and seat, the two sides and a back panel covering the lower half of the back of the cabinet. While this device can be used as an adult's portable step or table, as a storage cabinet or as a child's toy, it fails to teach the important multi-level supporting and holding structure of the present invention.
The design patents to Morley, Culligan and Macho, et al. show various designs for step stools, but also fail to disclose or teach the many important features of the present invention.